A curable thermosetting resin composition comprising an epoxy resin and a curing agent thereof is widely used in composite materials, coatings, and other fields. In the application areas of electrical insulation composite materials and wave-transmitting composite materials, the glass transition temperature, the dielectric constant and dielectric loss factor, and the flame resistance are very critical technical indices. For example, for electrical insulation products such as laminated composite sheets and PCB boards, a high enough glass transition temperatures allows the material to be efficiently used in a high-temperature environment, and a low dielectric constant and dielectric loss factor contribute to the separation of a current carrying region from other regions. For wave-transmitting products such as mobile communication base station antenna covers, a low dielectric constant and dielectric loss factor can effectively increase the wave transmittance.
In order to achieve a high glass transition temperature, and a low dielectric constant and dielectric loss factor, the previous method is to add various materials to the curable thermosetting resin composition, for example, SMA (a styrene-maleic anhydride copolymer), a cyanate ester, a ternary copolymer of styrene-maleic anhydride-maleimide, and the like. Chinese Invention Patent No. CN 103842433 A discloses an epoxy resin composition containing a terpolymer of styrene, maleic anhydride, and maleimide, which can effectively reduce the dielectric constant and improve the glass transition temperature. In addition, the requirement for flame resistance is generally satisfied by introducing the elements halogen and phosphorus, for example, by using a halogen-containing epoxy resin, and adding a phosphorus-containing polyphenylene ether resin.
The requirements of high glass transition temperature, low dielectric constant and dielectric loss factor, and flame resistance are still failed to be met by the existing methods by adding a simple substance. In addition, the addition of inactive additives which contain no reactive functional groups capable of reacting with the epoxy resin will generally reduce other properties of the composition.